1. Field of the Invention
The present invention relates to an initialization routine of a hard disk drive, more particularly, to an apparatus and a process for sequentially executing initialization calibration routines divided whenever an interrupt occurs.
2. Description of the Related Art
For the past several decades, the progress of the computer technology has led the advancement of the modem communication industry as well as the rapid progress of software and VLSI technologies. According to this trend, the demand for auxiliary storage media of high speed performance and high capacity has increased, thus resulting in the advent of computer systems employing a small computer system interface (SCSI).
Generally, in a computer system one or more hard disk drives are connected to a SCSI controller. Each of hard disk drives (HDD) connected with the SCSI controller, writes data transmitted from a main controller on disks or reads data recorded on the disks and transmits it to the main controller under the control of the SCSI controller. The SCSI controller connected between the main controller and the HDDs controls the interfacing of input/output signals of the main controller and HDDs. The main controller supervises the overall operations of the host computer, and controls read/write operations of each HDD. Respective HDDs connected with the SCSI controller perform a series of initialization calibration routines whenever electric power is applied. The initialization calibration routines include the steps of driving a spindle motor to rotate the hard disk at full speeds; calibrating bias to all tracks of the disk; and measuring and calibrating a gain of each integrated circuit (such as a digital/analog converter, a voice coil motor driving IC, etc.) on the printed circuit board.
The above-described calibration routines are programmed to be executed in the initialization routine that is carried out every time power is applied to the drive in order to remove the non-linear characteristics that servo-control cannot compensate for. In a conventional hard disk drive employing a SCSI mechanism, there is problem in that it is impossible to respond a command input from an external system during execution of the calibration routines.
Particularly, in the conventional hard disk drive employing the SCSI mechanism, the initialization routine is executed upon applying electric power. A main code comprises an initialization routine embodying a series of calibration codes to be executed according to a code performance sequence. If an interrupt is attempted in response to a servo sector during the execution of the calibration code, the execution of the initialization routine of the main code (i.e. calibration code) can not be interrupted As a result, in the conventional hard disk drive employing the SCSI mechanism, there is problem in that it is impossible to respond to a command input from an external system when the calibration code is executed as one of the main code.
A method for initializing a drive and for periodically updating its calibration of an encoder and a head position servo is contemplated by U.S. Pat. No. 5,227,930 to William N. Thanos, et al., entitled Head Position Recalibration For Disk Drive; and a servo calibration method carried out during initialization is contemplated by U.S. Pat. No. 4,814,909 to David A. Brown, et al. entitled Data Transducer Position Control System For Rotating Disk Data Storage Equipment.